The Las Vegas fresh fish debate is one that continues to linger largely through misinformation. First, the majority of “fresh” sushi is actually frozen, per FDA regulations. This story from the New York Times is seven years old, but remains on point -

Second, sushi in Las Vegas has been a supply and demand issue. Ten years ago there was little of either. But no segment in the local restaurant industry has grown more in that time, both on the Strip and off. The demand has grown, and because there is so much commercial traffic, getting the product here in 2011 is not an issue. On the Strip alone, in a little over a decade, we have added RM Seafood (Mandalay Bay), Bar Masa (Aria), Blue Ribbon Sushi Bar & Grill (Cosmopolitan), Sensi (Bellagio), Yellowtail (Bellagio), RA Sushi (Caesar’s Foum Shops), Japponais (Mirage), Sushi Roku (Fashion Show Mall), Okada (Wynn), SushiSamba (Palazzo), Koi (Planet Hollywood), Shibuya (MGM Grande) and if we consider the Hard Rock to be part of the Strip, Nobu. And those are just places with sushi as a major focus, while many other Strip seafood restaurants also will do sashimi when they have the proper quality available. Michael Mina will almost always have something going at SeaBlue or American Fish, and we have also had some terrific “crudo’s” at Valentino, Nove and Circo. It would not be an exaggeration to say that over 50 new sushi restaurants have opened off the Strip since 2000. Because of the volume, and collective purchasing power, some of the best fish to be found in North America is now coming through Las Vegas each day.

John Curtas eats sushi often, both on and off the Strip, with many favorable reviews, and note that two of the places listed above even made the Top 10 list when he, Al Mancini and Mac Jacobson put together their “Eating Las Vegas: The 50 Essential Restaurants” guide last year, RM Seafood and Bar Masa. Sensi and Yellowtail also made the overall list, along with Sen of Japan off Strip. Here is a quick way to view some of the reviews of sushi restaurants he has done -

Back to the original post, if it is going to be late-night it might come down to the convenience of where you are staying (be on the lookout for late Happy Hours specials), but a personal favorite would be RM Seafood. Rick Moonen does a terrific job of sourcing.